MRI, the standard Ruby interpreter, has a serious problem with memory bloat in large Rails apps. It's quite common for me to see Sidekiq processes which are 1-2GB in RSS or even larger! It turns out that a large part of this memory usage is due to memory fragmentation

Lately I've been working on adding DTrace probes to Ruby 2.0. I am interested in using them to profile and improve rails startup time. Today I want to look at building a profiler with DTrace, finding slow method calls, and making some incremental improvements